ABSTRACT
Internet telephony has been increasingly explored and implemented as a viable communication tool in large corporations. A main component of enterprise internet protocol (IP) voice is the IP premise branch exchange (PBX), which functions the way a traditional PBX does. It allows calls to be transferred throughout the organization, it allows easy intra-enterprise calls, and it operates automatically. The IP PBX has paid off for the corporations using it through reduced manpower and by eliminating an entire (telephone) network. This chapter provides payoff ideas and an explanation of the technology behind the IP PBX. PBX manufacturers fulfilled this need by installing a mainframe computer into the enterprise and connecting a proprietary line card interface to either analog phones or proprietary digital phones. The connection out to the public switched telephone network was established through a trunk interface card.
